为研究火龙果色素在不同体积分数的乙醇溶液中的稳定性,以吸光度变化为指标,探讨火龙果色素在pH 5.0时,不同乙醇体积分数在不同温度条件下的稳定性.结果表明:乙醇不影响火龙果色素的紫外可见吸收光谱.在40℃和80℃时,火龙果色素降解符合一级反应,其降解速率常数k随着乙醇体积分数的升高而增大,其稳定性降低；而在4℃时,火龙果色素在乙醇溶液中的稳定性较好,其中在体积分数为0、16％、30％的乙醇溶液中稳定性较在体积分数为60％的乙醇溶液中好.此研究结果为含醇火龙果饮料的稳定性提供参考依据.%To investigate the stability of pigments extracted from purple pitaya (Hylocereus polyrhizus) in the ethanol solutions, the degradation of pigments in 0, 16% , 30% and 60% ethanol at pH5. 0 have been monitored by the change in spectroscopic absorption under the temperature of 4 °C , 40 °C and 80 °C, respectively. The maximum absorption of the extracted pigments in the given concentrations of ethanol kept constant at 534 nm. The degradation of the pigments followed first-order kinetics reaction and the rate constants raised with the increase in the temperature of ethanol from 40 °C to 80 °C. Moreover, the pigments exhibited better stability in 0, 16% and 30% ethanol solutions than that in 60% ethanol. Taken together, these results could provide scientific information for evaluation of the stability of pitaya wine.
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